André Leclerc, independent informatics consultant

	André Leclerc	informatics consultant

Some business modeling concepts

This page lists and documents some concepts on which the simple methodologies presented on the other pages of this site are based.

Basic definitions
An information system is a collection of interrelated components that input, process, store and output information needed to complete some tasks or achieve some goals. As long as it inputs data, does something with that data and generates some new data, it is an information system. Any system, whether it is an information system or a transportation system such as an automobile, is used by people to accomplish certain tasks, in various ways, while satisfying or abiding by certain needs or requirements of those people or of the environments in which they operate. Those environments, in which information systems are used, can vary greatly from one system to another, in terms of scope. That scope can be as large as an entire organization, or be limited to a specific department or service of an organization, or be even more limited, for example, to a single business task such as the processing of claims. A model is a representation of a perceived or foreseen reality done for the purpose of communicating a vision, experimenting with alternatives, or predicting behaviours. An organization chart models an actual organization, a floor plan of a building is a model of an actual layout of real walls, partitions, equipment and furniture, and an information system model is a representation of a real information system. A model can be more or less precise in its representation of reality. For example, a picture of an automobile is a less precise model of that automobile than a working prototype of that same automobile is, whatever the size of the prototype. Using the above definition of a model, a prototype is simply a model exhibiting more realism, interaction or usage possibilities than other types of models. A model allows requirements to be defined and specified in more or less details depending on the precision of its representation of reality.

Basic definitions

An information system is a collection of interrelated components that input, process, store and output information needed to complete some tasks or achieve some goals.

As long as it inputs data, does something with that data and generates some new data, it is an information system.

Any system, whether it is an information system or a transportation system such as an automobile, is used by people to accomplish certain tasks, in various ways, while satisfying or abiding by certain needs or requirements of those people or of the environments in which they operate.

Those environments, in which information systems are used, can vary greatly from one system to another, in terms of scope. That scope can be as large as an entire organization, or be limited to a specific department or service of an organization, or be even more limited, for example, to a single business task such as the processing of claims.

A model is a representation of a perceived or foreseen reality done for the purpose of communicating a vision, experimenting with alternatives, or predicting behaviours. An organization chart models an actual organization, a floor plan of a building is a model of an actual layout of real walls, partitions, equipment and furniture, and an information system model is a representation of a real information system.

A model can be more or less precise in its representation of reality. For example, a picture of an automobile is a less precise model of that automobile than a working prototype of that same automobile is, whatever the size of the prototype.

Using the above definition of a model, a prototype is simply a model exhibiting more realism, interaction or usage possibilities than other types of models. A model allows requirements to be defined and specified in more or less details depending on the precision of its representation of reality.

Categories of components
Another basic concept that complements the above definitions is the fact that the components of information systems fall into three (3) categories depending on the functions that they implement: The business components of an information system are those components that implement the essential business functions of that information system. For example, an information system supporting the home appliance repair business would have amongst its key business components a client component, an appliance type component and a repair event component. The user interface components of an information system are those components that allow people to use and interact with the business components. An information system's menus, screens, forms, messages and reports are examples of such user interface components. The technology interface components of an information system are those components that allow the business components to function using available information technology. An information system's data base manager, data communication manager, data encryption and decryption software, and transaction monitor are examples of such components interfacing with various information technologies.

Categories of components

Another basic concept that complements the above definitions is the fact that the components of information systems fall into three (3) categories depending on the functions that they implement:

The business components of an information system are those components that implement the essential business functions of that information system. For example, an information system supporting the home appliance repair business would have amongst its key business components a client component, an appliance type component and a repair event component.
The user interface components of an information system are those components that allow people to use and interact with the business components. An information system's menus, screens, forms, messages and reports are examples of such user interface components.
The technology interface components of an information system are those components that allow the business components to function using available information technology. An information system's data base manager, data communication manager, data encryption and decryption software, and transaction monitor are examples of such components interfacing with various information technologies.

Data as the main source of differentiation
Since all information systems manage data, it is the data being managed that is the main source of differentiation between information systems. One system can, for example, manage data on human resources (people) while another manages data on financial resources (accounts, budgets, etc) and yet another manages data on physical resources (buildings, vehicles, computers, etc). The operations performed by those different information systems on their respective data are very similar. All information systems have to input, validate, add, store, update, delete, search, select, display and disseminate data. However, the data being managed differ from one system to another. The data elements that are within the realm of an information system's business domain should be used to derive the properties of that system's business components.

Data as the main source of differentiation

Since all information systems manage data, it is the data being managed that is the main source of differentiation between information systems.

One system can, for example, manage data on human resources (people) while another manages data on financial resources (accounts, budgets, etc) and yet another manages data on physical resources (buildings, vehicles, computers, etc).

The operations performed by those different information systems on their respective data are very similar. All information systems have to input, validate, add, store, update, delete, search, select, display and disseminate data.

However, the data being managed differ from one system to another. The data elements that are within the realm of an information system's business domain should be used to derive the properties of that system's business components.

Constituent and functional specificities of business domains
Another important source of differentiation between information systems consists of their respective business domains, i.e., of the functions being implemented by their respective business components. For example, an information system supporting the private technical training business has business components that an information system supporting the public library business does not have, and vice versa. Different components imply different functions. Different systems may have similar business components but those apparently similar components usually perform different functions or perform similar functions in different ways. So, what those functions are and how they are used by the users of an information system is important to know. Use cases should be written to document the functionality offered by an information system to its users. A use case of an information system is a typical use of that same system, in which certain actors use certain functions or capabilities of the information system to achieve a specific business goal or produce specific results.

Constituent and functional specificities of business domains

Another important source of differentiation between information systems consists of their respective business domains, i.e., of the functions being implemented by their respective business components.

For example, an information system supporting the private technical training business has business components that an information system supporting the public library business does not have, and vice versa.

Different components imply different functions. Different systems may have similar business components but those apparently similar components usually perform different functions or perform similar functions in different ways.

So, what those functions are and how they are used by the users of an information system is important to know.

Use cases should be written to document the functionality offered by an information system to its users. A use case of an information system is a typical use of that same system, in which certain actors use certain functions or capabilities of the information system to achieve a specific business goal or produce specific results.

Information systems as assemblies of business components
Consequently to the above concepts, the business components of an information system must not only embody all of the system's data but also implement all of the system's data management operations and carry out all of the system's use cases. To embody the data and implement the operations and functions, the business components of an information system have properties carrying the data and methods operating on those data. Properties are also known as fields, elements, attributes or characteristics, and methods are also known as operations. The business components also need to be assembled together or associated with each other in order to implement all of the data management operations and carry out all of the use cases of the information system, as many of those operations and use cases might require the cooperation of many different components.

Information systems as assemblies of business components

Consequently to the above concepts, the business components of an information system must not only embody all of the system's data but also implement all of the system's data management operations and carry out all of the system's use cases.

To embody the data and implement the operations and functions, the business components of an information system have properties carrying the data and methods operating on those data. Properties are also known as fields, elements, attributes or characteristics, and methods are also known as operations.

The business components also need to be assembled together or associated with each other in order to implement all of the data management operations and carry out all of the use cases of the information system, as many of those operations and use cases might require the cooperation of many different components.